The present disclosure relates generally to turbine engines and, more specifically, to a post-shutdown cooling system for a turbine engine.
Turbine engines, such as turbofan engines, experience several different phases of operation including, but not limited to, startup to idle speed, warmup, acceleration to higher power and speed for takeoff, climb, cruise, deceleration to lower speed and power for descent, landing and taxi, shutdown, and cool-down. Turbine engines may cycle through the different phases of operation several times a day depending on the use of the aircraft to which the turbine engines are attached. For example, a commercial passenger aircraft typically shuts down its engines in between flights as passengers disembark from the aircraft. At shutdown, residual heat within the turbine engine can result in the formation of thermal hotspots and thermal gradients within the turbine engine. The thermal hotspots and thermal gradients can result in degradation and coking of fluids, such as fuel and oil, that remain in the turbine engine after shutdown. Moreover, thermal deformation caused by the residual heat can result in contact-related damage between the rotating and stationary components of the turbine engine during engine startup, thereby reducing the service life, performance, and operability of the turbine engine. In addition, special startup procedures or engine startup delays are sometimes implemented to reduce contact-related damage, which can result in increased startup time and delay between flights.